The Evolutionary Transition from Anoxygenic to Oxygenic Photosynthesis

BLANKENSHIP, SUMEDHA SADEKAR, AND JASON RAYMOND I. Earliest Evidence for Photosynthesis and the Nature of the Earliest Phototrophs II. Structural Conservation of the Core Structure of Photosynthetic Reaction Centers During Evolution III. The Structural and Mechanistic Differences Between the Anoxygenic Reaction Centers of Type II and Photosystem II of Oxygenic Organisms IV. Evolutionary Scenarios for How the Transition from Anoxygenic to Oxygenic Photosynthesis May Have Taken Place V....

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Chlorophylls are the product of a very long (17 or more steps) biosynthetic pathway that probably, at least in part, recapitulates their evolutionary development. This idea was first proposed by Sam Granick and is known as the Granick hypothesis (Mauzerall 1992). The first half of the biosynthesis of chlorophylls is identical to heme biosynthesis and presumably reflects the more ancient origin of cyto-chromes in nonphotosynthetic organisms (Beale 1999). The first committed step of...

Criticism And Defense Of The Hydrogen Hypothesis

The hydrogen hypothesis has received some criticisms that are to be taken seriously and some that are not. The most serious critique has come from Cavalier-Smith (2002), whose main complaints have been twofold. First, he has lamented the lack of a specific selective pressure or biological rationale behind the origin of the nucleus. This criticism has recently been addressed with the suggestion that one can account simply and directly for the origin of the nucleus itself (more specifically, for...

Oxygenic Photosynthesis Across The Eukaryote Tree Of Life

Photosynthesis is widespread among eukaryotes (see Figure 1) as a result of multiple events and a variety of different mechanisms. Originally, eukaryotes (specifically the Archaeplastida) acquired photosynthesis from cyanobacteria (primary endosymbio-sis see Section II.D.). However, this primary endosymbiont has subsequently been passed around among eukaryotes multiple times, probably ever since the first plas-tid was established and continuing to the present. This lateral acquisition of...

What Is Primary Production

On Earth, six major elements, H, C, O, N, P, and S overwhelmingly comprise the ingredients of life (Schlesinger 1997). With the single exception of P, the elements that form the major biopolymers, including proteins, lipids, polysaccharides, and nucleic acids, are incorporated primarily in reduced form that is, they have received electrons and or protons from some source. Indeed, electron or hydrogen transfer (redox) reactions form the backbone of biological chemistry (Mauzerall, Chapter 2,...

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Acantharea Diploconus fasces, Lithoptera mulleri, Amphilonche elongata, Acanthometra pellucida Euglyphid amoeba Paulinella chromatophora Testate amoeba Amphitrema flavum, Hyalosphenia Foraminifera Globigerina bulloides, Globigerinoides spp. Globigerinella siphonifera, Orbulina spp., Peneroplis spp., Sorites spp., Archaias spp., Borelis spp., Calcarina spp. Chromalveolates Alveolates Ciliates Elphidium spp., Nonion germanicum, Nonionella Stella, Bulimina elegantissiTna Climacostomum virens,...

Structural Conservation Of The Core Structure Of Photosynthetic Reaction Centers During Evolution

Proteins sharing a common evolutionary origin have high primary sequence identity and similar three-dimensional structures. This sequence identity decreases and the structural similarity diminishes with increase in evolutionary distance between proteins. Below about 25 sequence identity, the sequences are said to be in twilight zone of molecular evolution studies (Doolittle 1986 Rost 1999). In such situations, it is usually not possible to reliably infer common ancestry from sequence...

Overview

The evolution of the light-harvesting antennas must be intimately connected with the evolution of mechanisms for getting rid of excess excitation energy, especially in an oxygen-rich environment. Carotenoids are well suited as energy dissipators, so it is no surprise that they are found along with Chls in most parts of the photosynthetic apparatus reaction centers (mostly P-carotene), the internal antennas of PS II (CP47 and CP43), the IsiA Pcb antennas of cyanobacteria, and the LHC superfamily...

Intermezzo

The editors of this volume requested that I discuss in more detail the possibility that the host was a heterotroph, that the mitochondrial endosymbiont was an anaerobic photosynthesizer, and that the benefit of that symbiosis was carbohydrate production for the host. The most explicit version in the literature that would come close to that suggestion was formulated by Dennis Searcy (1992, 2002) it is based on sulfur cycling entailing a Thermoplasma-like (a prokaryotic, not a eukaryotic) host...

Overview Of The Tree

Overview The Tree

Most eukaryotes can be assigned to one of eight major groups, six of which can be further grouped to make three supergroups (see Figure 1). Opisthokonts include animals, fungi, and several primitively single-celled lineages. Amoebozoa consists mostly of naked amoebae with lobose pseudopo-dia plus the social amoebas. Together, Amoebozoa and Opisthokonta form the supergroup unikonts, probably the only major group of eukaryotes to be ancestrally uniflagellate (Richards and Cavalier-Smith 2005)....

Cell Evolution With And Without Endosymbiosis

This book is mainly about photosynthesis, and many chapters deal with eukaryotic photosynthesis, which took root in the cyano-bacterial origin of chloroplasts via endosymbiosis. The host that acquired the cyanobacterial ancestor of plastids was certainly a eukaryote and certainly possessed mitochondria (see Fehling et al., Chapter 6 Hackett et al., Chapter 7, this volume). This chapter deals with the question of whence that eukaryote and its mitochondria arose. On the issue of eukaryote...

Prebiotic Photochemistryuv And Oceanic Photochemistry

The lack of oxygen, and thus of ozone, in the prebiotic atmosphere allowed the full spectrum gt 180 nm of sunlight to penetrate to the oceans Figure 1 . Liquid water absorbs strongly at wavelengths less than 180 nm. Ions such as chloride, sulfate, and phosphate are thus protected, but anions such as Br- and I- would absorb this plentiful UV, forming reactive oxidizing radicals and solvated electrons for details see Mauzerall 1992a, 1995, and Table 1 . The quantum yields are gt 0.1 but less than...

Conclusions

The standard model of eukaryote and mitochondrial origin posits that the host was a eukaryote related to archaebacte-ria, that the prime advantage of the mitochondrion at the onset of symbiosis was improved ATP yield from glucose by virtue of oxygen respiration, and that the nucleus arose before the mitochondrion. It predicts that primitively amitochondri-ate eukaryotes should exist, and it cannot directly account for anaerobic mitochondria or hydrogenosomes. The hydrogen hypothesis Martin and...

Phycobilisomes

Phycobilisome Core

The phycobilisomes PBSs are complex macromolecular structures attached to the cytoplasmic or stromal surfaces of thylakoid membranes Figure 2 . They are found in cyanobacteria and two of the three lineages of algae with primary chlo-roplasts, the red and glaucophyte algae see Figure 1 . The PBS has been completely lost in the third primary lineage, that of the green algae and plants. The similarities between cyanobacterial and algal PBSs are one of the strongest pieces of evidence for the...